Open-hearth furnace



l.. L.. KNox OPEN HEARTH FURHACE March 15, 1927.

Filed Oct. 14. 1920 6 Sheets-Sheet 1 l l l l SMM 1 QMMu u attozmzgs March "15, 19.127v

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Patented Mar. l5, 127.

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LUTHER L. KNOX, OF BELLEVUE, PENNSYLVANIA, ASSIGNOR T KATE A. KNOX, 0F

BELLEVUE, PENNSYLVANIA. f

OPEN-HEARTH FURNACE.

Application filed October 14, 1920. Serial No. 416,792.

Figure 1 is a sectional plan view of an open hearth furnace embodying my invention.

Figure 2 is a section on the line II-II of Figure 1.

Figure 3 is a section on the line III- III of Figure 1.

Figure 4 is a section onthe irregular line IV-IV of Figure 3.

Figure 5 is a transverse vertical section through one of the-valve chambers, valve, and the adjacent ports.

Figure 6 is a sectional detail view show ing a portion of one of the air ports.

Figure 7 is a plan view of one of the valve bodies.

Figure 8 is a vertical section through a part of one end portion of an open hearth furnace and illustrating a modification, and

Figures 9 and 10 are sections taken respectively on the lines IX-IX and X- X of Figure 8.

My invention has relation to certain new and useful improvements in open hearth furnaces, and is designedto provide a furnace of this character with a-novel construction 4and. arrangement of gas and air uptakes, waste-gas ofi'takes, slag pockets, regenerators .and reversing valve mechanism for control- 30 ling the furnace and ports, whereby a more eiiicient operation of the furnace is made possible, and numerous other advantages are obtained, some of which Iare hereinafter pointed out.

The nature of my invention will be best understood by reference to the accompanying drawingsin which'I have shown pre-y ferred embodiments thereof and which will now be described, it being premised, however, that various changes can be made in the detailsof construction, arrangement and combination of the several parts, without departing from the spirit and scope of. my` invention as defined in the appended claims.

In these drawings, the numeral 2 designates the hearth or melting portion of the furnace and which is, in general, of any usual or suitable character and construction. 3 designates slag pockets, there being one of these pockets at each end of the furnace. each of said pockets being connected with the furnace through one or more offt-ake passages 4 and ports 5. In the construction shown there are three of the offtakes 4 at each endof the furnace (see Figure 1). '6

designate air supply ports, one at each end o f the furnace, and which are supplied with air through regenerators or checkers in any usual or suitable manner. Each of these air ports 6 has an upwardly and backwardly extending vportion 6a (see Figure 6) which leads mto a transversely extending ortion 6b, from which extend the air upta es 6, terminating at their upper ends in the downwardly and forwardly directed inlet portions 6d.

7 designates a gas port, one for each end of the furnace, and through which the gas is admitted through regeneralsors or checkers in theusual manner. Each of these ports 7 extends laterally, as shown at 7a, (see Figure 1) across and below one end of the furnace to the opposite side of the furnace` where it communicates with a transverse reversely extending portion 7b. The gas uptakes 7 c lead upwardly from the portl portions 7*', (see Figure 2) and terminate in the forwardly and downwardly directed discharge portion 7, As will be seen from Figure 4, the inlet portion 6d of the air intakes 6 is separated from the discharge portion 7 of the gas uptake by the arch 8, the air port extending over the ysaid arch and downwardly at each side of the said discharge portion of the gas port. The arrangement of the discharge portion of the air and gas ports is such that the air and gas mix and combustion takes place before the air and gas enter the furnace proper. Both air and gas preferably are under pressure and this port arrangement gives what might be termed a blow-torch burner, the effect of which is to obtain an earlier" and also a more complete combustion within the furnace chamber.v

The offtake ports 5 are arranged above the arch 9 which separat-esl them from the discharge portion of the air inlet ports, and also extend downwardly at the` sides of the air and gas inlet ports, as shown at 9a. in loo Figure 4. By reason of this construction and arrangement, a large portion of the waste gases from the furnace chamber are not required to travel upwardly from the arch 9 in order to reach the ofi'takes 4, but can enter the otakes through the side portions 9a at a lower level. This not only gives a better outlet arrangement for the Waste oii'take ports 5. c The arches 9 may be effectively protected by'any suitable water-cooled arrangement, such as. indicated at 9h (see Fi rc2).

ach of the slag pockets 3 has a port 10 which opens into a valve chamber 11 connected by a port 12 with one of the air inlet lports 6, as bestshown in Figure 3. lEach slag pocket is also connected by a port 13 with another valve chamber 14 which communicates by a port 15 withan adjacent gas inlet port 7. Each of the valve chambers 11 and 14 also leads to a regenerator or checker,

one of which is shown at 15EL in Figure 4. The regenerators or checkers may be of any usual or suitable character.

Each pair of ports 1() and 12 and 13 and 15 is arranged to be controlled by a reversible valve 16, or 17. In the construction shown each of these valves consists of a hollow metal body to which is secured a hollow stem 18 which extends upwardly through the upper arched wall of the valve chamber and through a suitable water-seal 19, its upper end portion being connected to\-a suitablesupply pipe 20 for the introduction of water or other cooling liquid. The valve stem is bent horizontally or ofl's'et between the vertical arm thereof which extends upwardly, as above described, and the valve, so that when the stem is rotated about its vertical axis the valve will be' moved from a position to scat over the port 1() to a position to seat over the port 12, or vice versa.

and 5. .In order to permit the valve to be unseated at the beginning of its reversing movement and-to be seated at the end of its reversing movement, the valve and its stem are made capable of a vertical lift. This may be imparted by any suitable means, such as the ower c linder 21. The rotary movement of) the va ve may also be effected by any suitable means such as the rack and pinion devices shown at 22 in Figures 1 and 4, the inion members being made suiiiciently road faced to permit of the above described vertical movement of the valve while remaining in gear with the actuating racks. These gears may be operated by power cylinders 24. v

The operation is as follows :-In Figure 3 the valves are shown in the position they occupy when gas and air are entering the right hand end ofthe furnace and the waste gases are coming out at the left hand end of the furnace.

while each of the ports 1() and 13 is closed by the valves. The gas and air from the respective checkers ory regenerators therefore pass into the valve chambers 11 and 14 and thence by the respective ports 6 and 7 to the furnace. At the outgoing end of the fur- The action in this respect will be` fully understood by reference to Figures 3 In this position it will be seen that each of the ports 12 and 15 is open nace, the ports 12 and 15 are closed by the valves, while the ports 10 and 13 are open. The waste gases, therefore, pass down the offtakes 4 and directly into the slag pocket 3. From this pocket the flow out in a divided stream through t e` two ports 10 and 13, and thence to the respective regen# erators at that end of the furnace.

It will be noted that the waste gas offtakes are entirely separate and independent of. the air and gas inlet and supply orts throughout the entire length of the sai offtakes between the furnace chamber and the slag pocket. It will also be noted that it is only necessary to provide a single `slag pocket at each Iend of the furnace, the outflow from each of these pockets being divided between the gas and air regenerators at that end of the furnace.

In the construction shown, each of the valves 16, 17 may be protected by a refractory covering 17a which can be retained in place by ribs or ianges 17b formed on the metal body, as shown in Figures 5 and 7. The bent portion of the hollow valve stems may be protected by a suitable covering, as indicated at 18, in Figure 5. The valve seat portions of tlie`ports 10 and 12 and 13 and 15 may be protected by water-cooled members 25.

If desired, the gasand air may be still more effectively mixed before being introduced into the furnace by a construction such as `shown in Figures 8, 9 and 10. In this case, instead of there being a single gas inlet port 7 at each end of the furnace with a single air port arranged to discharge over and at the sides of the gas port, as above described, there is provided an alternating arrangement of gas ports 26 and air ports 27 placed side by side, each gas port 26 having an uptake 28 -communicating with the main gas inlet port 29; and each air inlet 'port 27 having a connection with an uptake 30 from the main 'air inlet port 31. The latter is also formed with a portion 32 which extends over the series of ports 26 and 27, thereby giving an additional supply of air at the discharge ends of said ports. By this construction a very thorough and effective mixing of the air and gas may be had at the point of combustion and before discharge into the furnace chamber.

Thefadvantages of my invention will be apparent to those familiar with open hearth furnaces, since it provides a construction which results in a more effective operation of the furnace due to better and more complete combustion. The air and gas inlet vports being separate and independent from the oftake orts are prevented from being clogged or lled by waste aroducts of coinbustion, and the life of t e port walls is also greatly extended. Inasmuch as none of the waste gases pass out through the gas menate and air ports, the Walls of these ports can he made much thinner', and the construction can be so designed as to provide for much greater eiciency of the furnace. That is to say, these ports can be designed and constructed Wholly from the standpoint of combusti-on efiiciency.y The invention also ohviates the necessity' of more than one slag pocket at each end of the furnace and permits of a very simple port arrangement as Well as the use of a simple reversing valve arrangement.

It Will readily be understood that the details of my invention may be varied Widely Within the spirit and scope ot the appended claims. j

l claim:

1. An open-hearth furnace having gas and air inlet ports at eachend, separate otake' ports extending above said inlet ports, and gas and air-reversing chambers into which the inlet ports open at each end of the furnace, said reversing chambers having lateral and upper Walls which separate said chambers from the said offtake ports, substantially as described.

2. An open hearth furnace having air and gas ports, andoiftake ports which are separate and independent of the air and gas ports throughout their entire length from the furnace chamber to regenerators, substantially as described.

3. An open hearth furnace havinga plurality of gas and air ports arranged in alternating relation at each end of the furnace, an arch over the said ports, and a secondaryair supply port extending over said arch, substantially as described.

a. An open hearthv t'urnace having a plurality of gas and air ports arranved in alternating relation at each end o? the furnace, an arch tor said ports, and an ofi'- talre above said arch, substantially as described 5. nopen hearth furnace having a plurality of gas and air discharge ports at each end of the furnace, an arch over each set of said ports, an oitake above the arch, and gas and air sup ly ports which are. independent of the o takes, substantially as described.

6. An open hearth furnace having gas 'and air ports at each end, a regenerator connected to each port, an ottake port at each end which is separate from the gas and air ports, a slag pocket at each end connected to the atitake port at that end, and valve means for passing the air and gas Jfrom their respective regenerators directly to the gas and air ports independently of the slag pocket, and for passing the Waste gases from the uptakes through the 'slag pockets, and thence to the regenerators, substantially as described.

Y. An open hearth turnace having at each end a single slag pocket, an oti'take leading from the furnace chamber to said pocket, two valve chambers adjacent each of said pockets, an oiitake port directly connecting each valve chamber With the adjacent pocket, a gas supply port extending directly from a regenerator to and through onel of said` valve chambers, an air supply port extending directly from a regeneratorA to and through the other of said chambers, and valve means in said chambers for controlling said ports, substantially as de-l scribed.

8. An open hearth furnace havin at each end a single slag pocket, an o take leading from the furnace chamber to said pocket, twovalve chambers adjacent each of said pockets, a ort connecting each valve chamber with t e adjacent pocket, a gas supply port extending through one of said valve chambers, an air supply port extending through the other of said chambers, and valve means in said chambers for controlling said ports, togetherwith regenerators directly connected to the valve chambers, substantial] as described.

9. An open hearth turriace having a single slag pocket at each end, an. o'take leading from the furnace chamber to each of said pockets, two valve chambers adjacent 95 to each of said pockets, a port connecting each valve chamber with the pocket, a gas supply port extending through one of said valve chambers, an air supply port extending through the other of said valve chambers, and a airof reversing valves at each end oithe` urnace, each of said valves bey. ing movable above a vertical axis from a position to close the port leading from the slag pocket to its valve chamber to a po- 105 sition. to close the port leading from said valve chamber to the adjacent supply port, and vice versa, substantially as" described.

10. An open hearth furnace having a single slag pocket at each end, an od'take leadno ing from the furnace chamber to each of said pockets, two valve chambers adjacent to each of said pockets, a port connecting each valve chamber with the pocket, a gas supply ort extending through one of said M5 valve' c ambers, an` air supply ortextending through the other of said valve chambers, and a pair of reversing valves at each end of the furnace, each of said valves being rotatable about a vertical axis from a 120 seating position over one port toa seating position over an adjacent port, substantially l as described.

l1. in open hearth furnace having a r single slag pocket at each end, an odtalre 320 leading from the turnace chamber to each of said pocket two valve chamrs adjacent tdeach of said pockets, a. port connecting each valve chamber With the pocket,

a gas supply port extending through @ne of 830 said valvel chambers, an air suppl port extending through the other of sai yvalve chambers, and a pair of reversing valves at each end of the furnace, each of said valves being rotatable from a seating position over one port to aseatingl position over an aflacent port, and also aving means whereby 1t may be moved vertically to seat and unseat it, substantially as described.

12. An open hearth furnace having two c adjacent ports; a valve having a bent stem and rotatable to move Vthe valve from one of said ports to the other, and means for mamas rotating said valve, substantially as described.

13. An open hearth furnace having two adjacent ports, a valve having a bent stem and rotatable to move the valve from one .of said ports to the other, and means for LUTHER L. KNOX. 

